1. Field
The disclosed system and method relate to a data terminal apparatus, and more particularly to a data terminal apparatus which is capable of performing a facsimile transmission operation through a local area network avoiding a communications error due to a delay time.
2. Description of the Related Art
There has been developed a data terminal apparatus which is capable of transmitting facsimile image information to a facsimile machine which is connected to a public switched telephone network (PSTN), via a so-called network facsimile machine. The network facsimile machine is capable of exchanging information such as electronic mail with other data terminals via a local area network and the Internet, as well as exchanging facsimile data with other facsimile machines via the PSTN.
One way for transferring facsimile image information from a data terminal to an arbitrary facsimile machine which is connected to the PSTN is to send an information transfer request to the network facsimile machine using the electronic mail. However, the electronic mail may be inferior in an aspect of immediacy of transmitting information since the local area network normally employs a mail server system in which the electronic mail is transferred to another data terminal, including the network facsimile-machine, via a mail server.
If a facsimile application which is included in the data terminal apparatus is configured to activate and to use a facsimile modem of the network facsimile machine as if using a facsimile modem of the data terminal apparatus, the immediacy of transmitting information may be greatly increased. In this case, the facsimile application software of the data terminal apparatus carries out the communications operation with the network facsimile machine through the local area network. Accordingly, delay times between commands in accordance with the Group 3 facsimile communications procedure and responsive signals corresponding to the commands may be unstable due to a varying amount of local area network traffic. A delay time that exceeds a predetermined allowable time period may cause an error of the facsimile application software.
However, these systems do not allow users to perform a facsimile transmission operation from a data terminal apparatus to a network facsimile machine via a local area network with an increased immediacy of transmitting information and without causing a communications error.
The present application provides a data terminal that can be coupled to a local area network. In one embodiment, the data terminal includes a first facsimile communications device and a second communications device. The first communications device performs a standard facsimile communications operation with respect to an information transfer request to a different data terminal through the local area network in order to transfer facsimile image information via the different data terminal to an arbitrary facsimile machine which is connected to a public switched telephone network. The different data terminal is coupled to the local area network and the public switched telephone network. The second facsimile communications device performs the standard facsimile communications operation with the first communications device and receives information, including a telephone number of the arbitrary facsimile machine, image information to be transferred, property information of the image information, and identification information of the data terminal. The second communications device then performs the standard facsimile communications operation using the information received from the first communications device with a different data terminal through the local area network after completing the standard facsimile communications operation with the first communications device. The second communications device is operatively connected to the first facsimile communications device and the different data terminal via the local area network.
The second communications device may control the standard facsimile communications operation with the first communications device to perform throughout a plurality of facsimile communications steps which are defined as phases A through to E in accordance with a Group 3 facsimile communications procedure.
The second communications device may set a redirect mode to perform at least one of the plurality of phases A through to E of the standard facsimile communications operation directly between the first communications device and the different data terminal.
The second communications device may set the redirect mode to perform the phase C of the standard facsimile communications operation directly between the first communications device and the different data terminal.
The second communications device may measure a delay time in the communications with the different data terminal by sending a test command to the different data terminal. Then, the second communications device may determine if the delay time is smaller than a predetermined value. Further, the second communications device may perform the standard facsimile communications operation under the redirect mode between the first communications device and the different data terminal when the delay time is smaller than the predetermined value, and perform the standard facsimile communications operation first with the first communications device and then with the different data terminal when the delay time is greater than the predetermined value.
The second communications device may set the redirect mode before the standard facsimile communications operation and measures the delay time with relative to a plurality of modem commands which are sent from the first communications device to the different data terminal.
The present application also provides an electronic communications system that is capable of transmitting facsimile information from a data terminal to at least one facsimile machine. In one embodiment, the system includes a plurality of data terminals, and a plurality of different data terminals, a plurality of facsimile machines. Each of the plurality of data terminals is coupled to a local area network. Each of the plurality of different data terminals is coupled to the local area network and to a public switched telephone network. Each of the plurality of facsimile machines is coupled to the public switched telephone network. Each of the plurality of data terminals includes a first facsimile communications device and a second communications device. The first facsimile communications device performs a standard facsimile communications operation with respect to an information transfer request to one of the different data terminals through the local area network in order to transfer facsimile image information via the aforementioned one of the different data terminals to at least one of the facsimile machines. The second facsimile communications device performs the standard facsimile communications operation with the first communications device and receives information. The information includes a telephone number of the aforementioned one of the facsimile machines, image information to be transferred, property information of the image information, and identification information of the one of the data terminals. The second facsimile communications device further performs the standard facsimile communications operation using the information received from the first communications device with the aforementioned one of the different data terminals through the local area network after completing the standard facsimile communications operation with the first communications device. The second communications device is operatively connected to the first facsimile communications device and the plurality of different data terminals via the local area network.